Since the late 19th century, the Prime Meridian at Greenwich has served as the reference line for Greenwich Mean Time, at longitude zero. This vibrant town is home to fascinating museums and vibrant markets. It boasts the O2 Arena, London's biggest arena for pop concerts and sporting events, the Greenwich Park, the Royal Observatory as well as the Planetarium. The host of attractions, pubs, bars, and restaurants in the area make it a popular spot for visitors from all over the globe.